x+y-2=0,求(x²-y²)²-8(x²+y²)的值.
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/09/01 09:32:06
x+y-2=0,求(x²-y²)²-8(x²+y²)的值.
x+y-2=0
x+y=2
(x²-y²)²-8(x²+y²)
=(x+y)²﹙x-y)²-8x²-8y²
=4(x²-2xy+y²)-8x²-8y²
=4x²-8xy-4y²-8x²-8y²
=-4(x²+2xy+y²)
=-4(x+y)²
=-4×2²
=-16
再问: =(x+y)²﹙x-y)²-8x²-8y² =4(x²-2xy+y²)-8x²-8y² 请问这两步是怎么做的
再答: (x+y)²﹙x-y)²-8x²-8y² x+y=2代入(x-y)²=x²-2xy+y² =4(x²-2xy+y²)-8x²-8y²
再问: =4(x²-2xy+y²)-8x²-8y² =4x²-8xy-4y²-8x²-8y² 好像哪写错了
再答: 4(x²-2xy+y²)-8x²-8y² =4x²-8xy+4y²-8x²-8y²
x+y=2
(x²-y²)²-8(x²+y²)
=(x+y)²﹙x-y)²-8x²-8y²
=4(x²-2xy+y²)-8x²-8y²
=4x²-8xy-4y²-8x²-8y²
=-4(x²+2xy+y²)
=-4(x+y)²
=-4×2²
=-16
再问: =(x+y)²﹙x-y)²-8x²-8y² =4(x²-2xy+y²)-8x²-8y² 请问这两步是怎么做的
再答: (x+y)²﹙x-y)²-8x²-8y² x+y=2代入(x-y)²=x²-2xy+y² =4(x²-2xy+y²)-8x²-8y²
再问: =4(x²-2xy+y²)-8x²-8y² =4x²-8xy-4y²-8x²-8y² 好像哪写错了
再答: 4(x²-2xy+y²)-8x²-8y² =4x²-8xy+4y²-8x²-8y²
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知x-3y=0,y≠0,求x²-2xy+y²分之2x+y×(x-y)的值
已知2x-y=10,求代数式[(x²+y²)-(x-y)²+2y(x-y)]÷4y的值?
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
已知方程组2x-y=10,x+2y=11,求(2x-y)³-(2x-y)²(x-3y)的值
已知|x+y+2|+(2x-3y-1)²=0 求 ⑴x、y的值 ⑵2x³-x²-3y
求因式分解(x-y)²-2(x-y)³和(x+y)(x-y)-x(x-y)
已知x²+4y²-6x+8y+13=0,求x-y/x+y的值.
已知y-2x=0,求3x²-2y²/(x+y)(x-y)的值
x²+y²-6x+8y+25=0求(x-y)-²